A vibratory screed device of this type is disclosed, for example, in US Patent U.S. Pat. No. 5,540,519. This publication discloses a vibratory screed device having an elongated vibrated screed beam which in cross-section is in the shape of an equilateral triangle. The vibrated screed beam is delimited by a flat underside, the first side of the triangle, by a first and second longitudinal side, the first and second sides of the triangle, and a top, specifically the apex or rib of the triangle. Furthermore, a handle assembly is provided which can be fitted, such that in principle it can be detached, on the vibrated screed beam, in particular on one of the longitudinal sides, such that it then slopes upwards with respect to the flat underside, transversely to the vibrated screed beam. A vibratory motor is fitted in the handle assembly, which motor transmits vibrations to the vibrated beam via a driven shaft and a vibratory rod fitted in the vibrated screed beam. Incidentally, it is pointed out that the installation based on the said patent which is available on the market has a different vibratory assembly without the vibratory rod fitted in the vibrated screed beam. In the case of the version obtainable on the market, the vibrations are transmitted to the outside of the vibrated screed beam from a vibration source fitted on the handle assembly.
As such, vibratory screed devices for levelling freshly poured concrete surfaces have already been known for several decades. In this context a very large number of vibrated screed beams of different constructions have already been designed for diverse specific applications. In general the requirements in respect of a vibrated screed beam for relatively wet concrete differ from those for relatively dry concrete. A further point is that vibratory screed devices of this type can be used in a manner in which they float on the concrete, but can also be used in a supported manner, in which case road forms, on which the ends of the vibrated screed beam bear, are placed at the side of the concrete surface or in the concrete surface. The intention with all of these vibratory screed devices is to level freshly poured concrete surfaces and, in doing so, also to compact the concrete by means of vibration. Depending on the specific application, a different vibratory screed device or at least a different vibrated screed beam must therefore always be used. This means that a number of different types of vibratory screed devices or at least a number of different types of vibrated screed beams must be kept in stock. There are manufacturers who respond to this by marketing various types of vibrated screed beams.